Tractor hitch and seal means therefor



Oct. 3, 1961 H. K. KIENZLE 3,002,570

TRACTOR HITCH AND SEAL MEANS THEREFOR Filed Aug. 27, 1959 2 Sheets-Sheet 1 FIG.|

INVENTOR. H. K. KIENZLE Oct. 3, 1961 H. K. KIENZLE 3,002,570

TRACTOR HITCH AND SEAL MEANS THEREFOR Filed Aug. 27, 1959 2 Sheets-Sheet 2 FIG.3

. rte

This invention relates to tractor draft structure and more particularly to improved seal means for sealing an opening adjacent to relatively movable components.

In the particular environment in which the invention finds utility, the relative movement between the tractor and the draft structure is radial to the major axis of an inherently resilient bar, which thus distinguishes the sealing situation from that involved in the usual rotary type. In an exemplary structure the tractor has a pair of transversely alined support elements which are formed as part of a lubricant-containing housing. The inherently resilient bar projects at opposite ends beyond the support portions forming these openings and the projecting ends of the bar are connected to draft structure which is subject to draft forces applied by a tractor-connected implement. The support portions provide fulcra for the ends of the bar and when the bar is displaced, it is stressed in bending so that intermediate portions thereof may be utilized to transmit a signal to control mechanism on the tractor. In this regard, the structure is applicable particularly to so-called draft control sys-' terns conventionally employed in the agricultural field and in which the use of the inherently resilient bar is a novel improvement as outlined in assignees copending application Ser. No. 730,743, filed April 16, 1958, now Patent Because of the bending of opposite ends of the bar and further because of the projection thereof through walls of the lubricant-containing housing, ordinary seals have been found ineffective, because they do not retain their sealing function for sufficiently long periods to establish them as commercially acceptable. Ordinary seals used in rotary shafting have been found incapable of performing the task. Accordingly, it is a principal object of the present invention to provide an improved seal especially adapted to accommodate relative movement between parts in which one of the parts projects through an opening and is subject to bending in directions radial to the ais of the opening. It is an important object of the invention to provide the seal in the form of a diaphragm having inner and outer annular portions respectively en- "circling and received by the bar and a portion of the support surrounding the opening. A further object of the invention is to provide an improved seal in which part of the material of the diaphragm is carried inwardly within an inner ring so as to form a tight fit with the bar. A still further object is to utilize in-conjunction with the seal a "retainer or guard ring which facilitates assembly of the seal on the bar or shaft.

The foregoing and other important objects and desirable features inherent in and encompassed by the invention will become apparent to those versed in the art as apreferred embodiment is disclosed, by way of example, in the ensuing description and accompanying sheets of drawings, the figures of which are described below.

FIG. 1 is a fragmentary elevation of a rear portion of a tractor and associated implement, the near wheel of the tractor being omitted in the interests of affording a better disclosure of the working components.

FIG. 2 is a schematic view, partly in section, showing the relationship of the controlling and controlled mechanism to the draft structure and bar.

, FIG. 3 is an enlarged fragmentary section as seen generally along the line 3-3 of FIG. 1.

fhlififil'fi i atented Get. 3, 1961 FIG. 4- is an enlarged fragmentary section of that portion of FIG. 3 indicated by the arrow bearing the encircled numeral 4.

The environmental structure chosen for purposes of illustration may be regarded as typical of structure found in the agricultural field wherein an implement is connected to a tractor by draft structure. in the present case, the numeral 10 designates the fore-and-aft body or support structure of a tractor, the rear portion of which includes. a lubricant-containing housing 12 in. which is carried part of the power train (not shown) of the tractor. The transmission housing 12 has oppositely extending axles 14, only one of which is shown, and each. axle carries a large rear traction wheel 16.

The draft structure is designated in its entirety by the numeral 18' and serves to connect to the tractor a trailing. implement, here a plow having a plow beam structure 20 and a pair of plow bottoms 22. The draft structure includes a pair of laterally spaced apart lower draft links 24 which are pivoted at their rear ends to the implement on a transverse axis at 26 and are connected at their forward ends to the tractor on a transverse pivot repre-- sented by a pair of coaxial pins 23. These pins are in. turn received in rearwardly projecting laterally spaced apart apertured cars 30 on what may be regarded as a. draft element in the form of an A-frame 32. The forward end of the A-frame is slotted at 34 and is mounted. via a pin 36 and a pair of cars 3%, rigid on the tractor body, so that draft forces in tension applied through thelinks 24 tend to shift the A-frame 32 rearwardly through.

Theamount and nature of the shifting is controlled by con-- necting the rear portion of the A-fr-arne 32 to the tractorby resilient means, and it is in this resilient means that.

a distance permitted by the length of the slot 3 the present invention resides.

hydraulic system. However, these details may be varied and are referred to herein as representative only.

Each end or support element 42 has a transverse opening 44 thercthrough, and the openings are coaxial on a transverse axis for the purpose of accommodating an elongated inherently resilient bar as, opposite ends of which, as at 48, project outwardly beyond the portionsv 42 to be received respectively by apertured parts 59 of the A-frame 32. Each opening is provided with a hardened bushing 52 which relatively closely encircles the proximate part of the bar 46. In a preferred embodi ment, the interior of the bushing is tapered as shown at 54 for controlling the degree of bending of the associated end portion 48. Likewise, each apertured portion 50 of the A-frame 32 may be provided with an interiorly tapered bushing 56. The bushing 52 provides. means at the opening 44 affording a fulcrum for the proseimate part of the bar 46, and the bushing 55 provides means whereby the end 48 of the bar is engaged by the-- It will be understoodj. of course, that the structure is symmetrical at opposite proximate part 50 of the A-frame.

sides of the longitudinal median plane of the tractor.

In a quiescent status of the structure, the bar 46 will be straight, and will be carried by the two fulcra or bush ings 52, with the end portions 48 respectively received by" When draft load is" applied to the draft structure by the implement and draft' links 24, the end portions 48 will be displaced rearwardly the bushings 56 in the A-frame.

.aooaero g as the bar 46 is stressed in bending. The direction of displacement will of course be radial as respects the axis of the openings 44'. In some cases, implement forces may be applied in such manner as to stress the links 24 in compression, in which case the ends 48 of the bar will be displaced forwardly. In either case, the bending of the bar is in directions radial to the aforesaid axis.

As the bar is stressed, irrespective of its direction, a midportion thereof will likewise be displaced, but in the respective opposite direction. The displacement of the midportion is utilized to transmit a signaling force to a signal member 58 which in turn transmits the signal to controllable mechanism on the tractor. This is outlined in detail in the patent referred to above and will be described here only briefly for the purpose of orientation. As is customary, agricultural tractors are equipped with a transverse rockshaft, and such rockshaft is designated here by the numeral 60, being carried by an upper housing part 62 attached to the transmission case 12 and having at opposite ends thereof lift arms 64 which are connected by links 66 respectively to the draft links 24. When the rockshaft 60 is rocked in a clockwise direction as seen in FIG. 1, the implement will'be lifted. Conversely, counterclockwise rocking of the rockshaft will cause the implement to be lowered. Variations i1 height of the implement are used to establish variations in its working depth. When the implement is raised to its maximum height, it is in a transport. position, with the plow bottoms 22 clear of the ground.

Also as is conventional, the rockshaft 60 may be powered by a hydraulic motor, here comprising a cylinder 68 and a piston '76, the rod 72 of which is connected via an internal arm 74 to the rockshaft. The; transmission of fluid under pressure to and from the cylinder 68 is, achieved via a valve 76 which is under the control of the signal member 58 as well as a manually settable lever '78. The signal member 58 and hand lever 78 are interconnected by difierential linkage 80 which also has a connection to a rockable member 82 for the valve 76. This valve includes a high pressure passage 84 which may be connected to any suitable pump as at 86. A fluid line 33 extends between one endof the cylinder 68 and a chamber 90 in the valve 76, and this chamber is selectively connectible to the high pressure line 84 or to a sump or reservoir line 92. For this purpose, the rockable member 552 controls a pair of poppet valves 94 and 96, both of which are spring-loaded to closed positions. When the rockable member 82 is rocked in. a clockwise direction, the poppet vlave 94 is raised from its seat and fluid under pressure is directed to the rear end of the piston 76, forcing the piston to the right, or forwardly, and rocking the rockshaft 60 in a clockwise direction to raise the implement. Rocking of the member 82 in the opposite direction lifts the poppet valve 96 from its seat and fluid at the left hand or rear end of the cylinder flows to reservoir via 88-9092, the implement descending by its own weight in the one-way system here described. As will be clear, the poppet valves may be operated by force derived from either the hand lever. 78 or the signal member 53 via the linkage 80. For example, when the depth of the plow is initially set by the hand lever 73, the draft structure will be in'what may be regarded as a quiescentstatus,inwhich.casethe signal member 53, retained by a spring 98, serves as a fulcrum for the linkage 86 so that movement of the hand ever 78 operates through the linkage to elevateone or the other of the poppet valves 94 or- 96. Onceset, the plow will continue to operate'at the selected depth until changes in draft force occur, which may arise because of differences in soil texture, loss of. traction and soforth, all of which characteristics are familiar to those versed in the art. In the event that the draft force increases, the tension applied to the links 24 will be transmitted to the end portions 48 of the bar 46, displacing the end portions rearwardly and the midportion of the bar forwardly. Because of the spring 98, the signal member "38 Ca l will follow the midportion of the bar 46, and will operate through the linkage 30 in such manner as to lift the poppet valve 94, whereupon fluid under pressure will be transmitted to the cylinder 68 in such manner as to rock the rockshaft 6b in a clockwise direction, thus shallowing the plowing depth until the draft force equals oi' return r-'0 that initially set into the system by the hand lever 78. During operation of the system, the ends 48 of the bar are continually deflected or displaced and consequently this characteristic requires the use of an adequate seal between the bar 46 and each of the openings 44 or, more properly, the opening afforded between the inside diameter of the bushing 52 and the outside diameter of the associated bar portion 48. In any event, there is an opening to be sealed and whatever seal is employed is subject to the continual stressing of the bar and the displace ment thereof as the A-frame element moves relative to the support elements 42. In this environment, the invention aifords an improved seal, indicated in its entirety by the numeral 100. As best shown in FIG. 4, the seal means 100, at each side of the structure, comprises an inner annular portion or ring 102 of relatively rigid material, preferably steel, having a radially outwardly extending annular flange 104. The seal additionally in cludes an annular outer portion or ring 106 having an inwardly directed annular flange 108. The ring 106 tightly fits within an annular recess 110 formed in the support concentric with and bordering the opening 44. The inner ring 102, together with a liner to be described, tightly encircles the proximate part of the bar 46 and extending between the two rings is an annularfiradially' flexible diaphragm 112, preferably formed of any composite seal material and capable of radial flexing as will be described below. The outer marginal edge of the diaphragm is bonded or otherwise joined to the interior of the outer ring 106 in the area designated generally by the numeralltl t, and the inner marginal annular edge of the diaphragm is joined to the ring 102, preferably by a structure in which the flange 104 on the ring 102 is embedded in a slightly thickened portion of the diaphragm, which will be clear from FIG. 4. Further, a portion of the diaphragm material, as at 116, is carried inwardly of the inside diameter of the ring 102 so as to tightly fit the shaft or bar 46. Thus, the two rings tightly fit their respective parts, the inner ring 102, with its liner 116, fitting the shaft or bar 46 and the outer ring 106 tightly fitting the recess 110. The diaphragm 112,- being radially flexible, accommodates changes in the position of the end portion 48 of the bar as this end portion is displaced radially as respects the axis of the bar. Thus, although the diaphragm 112 is distortable, it is fully capable of recovering its original shape. Since the two rings are tightly connected to their respective parts, no leakage can occur, because flexing is taken entirely by the diaphragm 112. I

A further feature of the invention resides in a rigid ring, preferably steel, as indicated at 118. This ring is installed between the seal 100 and the proximate inner side of the A-frame portion 50. The purpose of the ring or retaining washer 118 at each side of the structure is to support the respective seals during assembly; that is to say, the rings prevent axial outward displacement of the seals which are first installed axially inwardly in the respective recesses 110, employing any suitable tool for this purpose. The A-frame 32 is then disposed. in such position that its openings as afforded by its bushings 56 are in register with the openings afforded in the support element bushings 52. The bar or shaft 46 is then inserted endwise from one side of the A-frame, through the support portions 42 and out the other side. It will be seen that as that bar 46 is pushed across the transmission housing, the end 48 at one side thereof will engage the seal at that side from the inside. The liner portion 116 will of course have an interference fitwith the shaft or bar and, without the support ring 118, the seal would be subject to being pushed out of its recess, or at least outwardly far enough to affect the tight seal between the ring 106 and the recess. After the bar 46 is properly located endwise, it is retained against axial loss by a pair of retainer pins 120, one at each side of the structure and received in the A-frame portions 50 diametrically as respects the axis of the shaft or bar 46.

As pointed out above, the diaphragm seals employs an interference fit on both the outside diameter of the'shaft and the inside diameter of the recess Since the diaphragm deflects and the interference fits are not altered by displacement of the end portion 48 relative to the support portion 42, there can be no leakage past the seal. Further, the type of seal disclosed here is relatively insensitive to dirt or corrosion, since there is no sliding contact between relatively movable seal parts. As will be clear, the environment in which the seal means is used is one involving considerable dirt and corrosion, which would not be tolerated by ordinary seals. A further advantage of the present seal is that assembly thereof is less critical than the conventional seal, since there are no delicate lips or sealing surfaces to be protected during installation. 1

Features and advantages other than those outlined here will readily occur to those versed in the art, as will many modifications and alterations in the preferred embodiment illustrated and described, all of which may be achieved without departure from the spirit and scope of the invention.

What is claimed is:

1. In a tractor having a fore-and-aft body and draft means connectible to an associated implement, the combination with the draft means of: a pair of supports spaced apart and alined transversely of the body, each support having a transverse opening therethrough and said openings being coaxial on a transverse axis, and each support having an outwardly facing annular recess larger than and concentric with its opening; an elongated inherently resilient bar disposed transversely of the supports and through the openings and having opposite ends projecting outwardly beyond the respective supports and connected to the draft means to receive draft forces from said draft means; bar-engaging means on each support at the respective opening and providing a fulcrum inwardly of the respective recess and outwardly beyond which the respective end of the bar projects so that draft forces applied to the draft means will stress the bar in bending so as to displace the ends of the bar radially of the respective recesses; and an annular seal received in each recess and including an inner ring encircling the bar and having an inside diameter slightly larger than the outside diameter of the respective part of the bar encircled thereby, an outer ring tightly received in the recess, a radially flexible annular diaphragm joined to and extending between said rings and capable of radial flexing upon displacement of the respective end of the bar, and said diaphragm having an inner marginal cylindrical portion eX- tending axially within the inside diameter of the inner ring to form a tight fit with said respective part of the bar.

2. The invention defined in claim 1 in which: said inner ring has an annular radially outwardly directed flange of lesser diameter than the respective recess and said flange is joined to the diaphragm.

3. In combination: a support element; a movable element alongside the support element; one of said elements having an opening therethrough providing a fulcrum; an inherently resilient bar extending through the opening and engaging the fulcrum and having a portion projecting beyond said fulcrum and engaging the other element so that relative movement between the elements in a direction transverse to the length of the bar stresses the bar in bending so as to displace the projecting bar portion radially as respects the axis of the opening; and seal means between the projecting portion of the bar and said one element, including an inner ring of relatively rigid material loosely surrounding said bar portion, an outer ring of relatively rigid material concentric with the opening and fixed to said one element, and a radially flexible diaphragm of pliable material joined to and extending between said ring and capable of radial flexing upon displacement of said bar portion, said diaphragm having a coaxial sleeve of pliable material tightly encircled by the inner ring and tightly encircling the bar portion to function as a liner for said inner ring.

References Cited in the file of this patent UNITED STATES PATENTS 1,529,874 Culbertson Mar. 17, 1925 2,162,104 Mosher June 13, 1939 2,426,701 Miller Sept. 2, 1947 2,510,414 Philbrick June 6, 1950 2,797,940 Michener et a1. July 2, 1957 FOREIGN PATENTS 1,130,866 France Oct. 8, 1956 

